Dietary intakes and plasma concentrations of folate in healthy adolescents.

Dietary intakes of folate and concentrations of plasma folate were obtained from healthy adolescents of families having low or high income. Results were tested statistically in relation to ages and to sex maturity ratings of the subjects. Maturity was a significant factor and age was not. Boys had higher dietary intakes of folate than girls, and family income was not significant. Low folate intakes are in general attributed to incomplete tables of folate content of foods and suggest a need for revision of existing standards. Plasma folate concentrations were higher in girls than in boys at all maturity ratings but both sexes showed decreasing concentrations as they became more mature. The paradox of increased dietary intake associated with decreased plasma folate concentration reflects increased need of folate for cellular manufacture associated with adolescent growth, particularly in boys. Plasma folate concentrations were subnormal in 9.4 percent of boys and 4.7 percent of girls from low-income families. Girls of higher income families had higher plasma folate due to their taking nonprescribed vitamin preparations containing folic acid. Family income did not affect dietary intakes but, either income or cultural pattern indirectly affected plasma folate concentrations. The study demonstrates the value of relating nutritional investigations to maturity ratings.